Hyperglycemia (CSF glucose concentration of 5 mM) increases the number of SCO cells with constricted morphology.

(A-C) TEM analysis when the CSF glucose concentration was 5 mM. SCO cells with constricted morphology and intercellular spaces in areas close to the ventricle were observed. Scale bar: A, 10 μm; B, 2 μm; C, 4 μm. (D) Apical region of SCO cells. We detected blebs, cilia, and microvilli and extracellularly disaggregated SCO-spondin. MVBs-like EV were secreted (D, insets). Exosome-like vesicles intermixed with secreted SCO-Spondin and cilia were also observed (arrows and insets). Scale bar: D, 1 μm; higher magnification, 0.1 μm. (E) Dorsal ependymal cells. Scale bar: 5 μm. (F) Ependymal cell cilia. Floccular material associated with cilia membranes (arrow and insets). Scale bar: 0.5 μm; higher magnification, 0.2 μm. (G) Choroidal plexus cells showed a normal structure without secretory material outside the cells. Scale bar: 3 μm; higher magnification, 1 μm. N = 4. CSF, cerebrospinal fluid; EV, extracellular vesicle; MV, microvilli; MVB, multivesicular body; SCO, subcommissural organ; TEM, transmission electron microscopy. (TIF)